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Introduction to Linux - A Hands on Guide

This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter.
For more advanced trainees it can be a desktop reference, and a collection of the base knowledge needed to proceed with system and network administration. This book contains many real life examples derived from the author's experience as a Linux system and network administrator, trainer and consultant. They hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own.

Ufff, dual booting, the first thing that occurred to Patrick, was responsible. Or rather my not choosing the proper timezone in Windows together with the fact that Windows was set to adjust time based on internet sources. My timezone (Windows) was Central Time (-6.00) when in fact mine is -3.00. That's why my clock led by exactly 3 hours!

The three-character abbreviations are the time zone; in the conterminous US, there is Eastern, Central, Mountain and Pacific, there is Standard time and Daylight time and there is Time: thus, EST, CST, MST and PST during "normal" months and EDT, CDT, MDT and PDT during "daylight savings" months (Alaska and Hawaii are far west of those zones, they abbreviate as AKST and HAST).

The ART is simply the country code (AR) and Time (seems like Argentine only has one time zone?).

"Wide" countries have multiple time zone and the three- or more character codes are just a way to keep things on track. The basic rule is that every 10 degrees east or west of Greenwich is one hour; that's not political, it's physical. The way the time zone are carved out, though, is political (look at a world time zone map and you'll see that -- no straight lines there). This one is kind of cute: http://www.timeanddate.com/time/map/. There are places on the planet where some time zones are in half-hours (gotta wonder about that).

Argentina has two different times since some years now. And since about the same time we do not have daylight time. But should not the fact that we use standard time be reflected in 'ART', and be 'ARST'?

A remark that comes to my mind is, why so few man pages speak about the format of the command output? Example, 'date'.

When I run timeconfig I choose the option „Hardware clock is set to UTC” and I set the right time zone („Europe/Warsaw” in my case though „Europe/Paris” does the same – sets the time to the Central European one). Then I use date command to set the right date and time. Finally I run hwclock --systohc command to write the right time to BIOS.

In /etc/rc.d/rc.local_shutdown I set the same command:

Code:

# save time
/sbin/hwclock --systohc

In /etc/rc.d/rc.local I set the commands:

Code:

# adjust time
/sbin/hwclock --adjust ; /sbin/hwclock --hctosys

When I need to change the time I use the mentioned date and hwclock --systohc commands.

I don’t bother with --utc and --localtime switches because hwclock recognizes the valid settings using /etc/hardwareclock file.

The Windows thing

When you use dual booting with Linux and Windows the latter system spoils the time at the turn from the summer to winter and from the winter to summer (Widows makes the correction already made by Linux). To disable that find in Windows the time settings and switch off the correction for the summer/winter time.

The time thing

To check the right time in the different time zones use the following site:

I'm not quite done with this problem it seems, and for the moment I made this: Went to windows and disabled the network thing, leaving daylight disabled too. Now I'm waiting to have stable symptoms before I take any measure.

As to your advices, I'll try them later, not now as I have said. The saving of system time to the hw clock at shutdown, I think the OS does it by default, but I'll have an eye on it.

"What’s missing in the man date in your opinion?": Maybe I should know the meaning of ART but could not the manual say a word about the way the output specifies the country code and daylight condition?

There is a tide in the affairs of men.
Which, taken at the flood, leads on to fortune;
Omitted, all the voyage of their life
Is bound in shallows and in miseries.
On such a full sea are we now afloat,
And we must take the current when it serves,
Or lose our ventures.

The saving of system time to the hw clock at shutdown, I think the OS does it by default, but I'll have an eye on it.

You’re right: /etc/rc.d/rc.0 and /etc/rc.d/rc.6 do that. My settings are very old. Probably in those old times the system didn’t save the system time to the hardware clock so I had to do that. Or maybe I just doubled the default settings in /etc/rc.d/rc.local_shutdown unconsciously.